1. Field of Invention
Various exemplary embodiments relate generally to a semiconductor device and an operating method thereof, and more particularly, to a program method.
2. Description of Related Art
Semiconductor memory devices have a memory cell array for storing data and peripheral circuits configured to perform program operations, read operations and erase operations, and a control circuit for controlling the peripheral circuits. Memory cell arrays include memory blocks that have substantially the same structure. Each of the memory blocks includes a plurality of cell strings. When a program operation is performed, specific cell strings and memory blocks are selected.
During a program operation, a program permission voltage is applied to channels of the selected cell strings, and a program inhibition voltage is applied to channels of unselected cell strings. For example, the program permission voltage may be 0V, and the program inhibition voltage may be a power voltage VCC.
Unselected memory cells of the unselected cell strings are more effectively prevented from being programmed when the difference between a channel voltage and a program voltage is small. To reduce the voltage difference between the channel voltage and the program voltage, channel voltages of the unselected cell strings are increased through channel boosting.
Channel boosting is an increase in the channel voltage due to coupling between a pass voltage applied to unselected word lines and the program inhibition voltage applied to the channel. However, due to the characteristics of a semiconductor device, channel boosting may be reduced while a program operation is performed. When channel boosting is reduced, the channel voltage of the unselected cell strings may be reduced, and unselected memory cells may be unintentionally programmed.